Mount Desert Island in Hancock County, Maine, is the largest island off the coast of Maine. With an area of 108 square miles it is the 52nd-largest island in the United States, the sixth-largest island in the contiguous United States, and the second-largest island on the Eastern Seaboard, behind Long Island and ahead of Martha's Vineyard. According to the 2010 census, the island has a year-round population of 10,615.